By: MSF Staff and reviewed by Multiple Sclerosis Foundation Medical Advisory Board
Studies indicate that as many as half of all MS patients experience some difficulty in swallowing, a symptom called dysphagia (dis-FAY-juh). Dysphagia occurs more frequently in advanced stages of MS, although it can occur at any time during the disease course. To better understand dysphagia, it is helpful to first examine the normal swallowing process.
Swallowing isn't as simple as it looks! In fact, normal swallowing occurs in three distinct phases, the oral stage, the pharyngeal stage, and the esophageal stage.
The oral stage requires coordinated movement of the lips, tongue, jaw, and soft palate, as well as tension from the cheek and facial muscles. After the food is chewed and mixed with saliva, it is then moved from the front of the mouth to the back by the upward and backward movements of the tongue against the hard palate.
As the food reaches the back of the mouth, the swallowing reflex begins. This is the pharyngeal stage of swallowing, which requires highly coordinated movements of the soft palate, larynx and pharynx to transport the food through the pharynx into the esophagus.
During the esophageal stage, the masticated food (called bolus, meaning a lump of chewed food) enters the esophagus and is then transported to the stomach by a squeezing action of the throat muscles.
Diagnosis of Dysphagia
A thorough history and neurologic exam of the tongue and swallowing muscles is the basis for an initial diagnosis of dysphagia. An imaging procedure called a modified barium swallow is often used. This test requires the patient to drink or eat liquids and solids of various consistencies. Then a radiologic study with a video fluoroscopy traces the path of the contrast material, filming the swallowing. The speech/language pathologist (SLP) and radiologist are then able to determine the precise location and type of swallowing disorder.
Types of Swallowing Disorders
Delay in Pharyngeal Swallow
"There is a wide variability in swallowing disorders in individuals with MS," explains Jennie Lou, MD, Professor of Public Health and Occupational Therapy at Nova Southeastern University. "This is because of the wide variability in central nervous system damage in MS, the wide range of disease severity, and the patterns of exacerbation and remission."
"A delay in triggering the pharyngeal swallow is common in those with MS and may result in difficulty swallowing thin liquids, or frequently having a mouthful of saliva and sometimes choking on it," Lou explains. "Often, people with MS experience more difficulty swallowing liquids, particularly if there is a delay between the end of the oral stage of swallowing and the beginning of the pharyngeal stage. Sometimes, the airway remains open until the pharyngeal stage of swallowing has begun. This delay can increase the risk of the liquid slipping into the airway and lungs. When this occurs, the person may have a tendency to cough or choke when trying to swallow liquids."
Reduced Pharynx Wall Contraction
Reduced Pharynx Wall Contraction is another common swallowing disorder associated with MS. "With this type of ineffective swallowing, food can remain in the pharynx after the swallow. The residual food may fall or be sucked into the open airway when the patient breathes after the swallow."
Sometimes, when an individual coughs or chokes, the food or liquid is inhaled into the trachea rather than down the esophagus and into the stomach. If this happens, and the food enters the lungs, it can cause abscesses or pneumonia. If this occurs frequently, and the food or drink does not reach the stomach, malnutrition or dehydration can result. In addition, small amounts of food or liquid are sometimes unknowingly inhaled, which is called silent aspiration. Fortunately, there are things that can be done to avoid or alleviate these complications.
Fatigue and Dysphagia
The interaction between fatigue and dysphagia is important and all too often overlooked. "This interaction is very similar to fatigue with walking," Lou explains. "A person with MS may walk without difficulty, only to develop leg weakness if the walk is extended. Likewise, a person with MS may have no swallowing difficulty at the beginning of a meal, but may develop swallowing problems during a long meal, especially one involving extensive chewing."
Lou advises frequent rest periods during long meals or eating more often for a shorter period of time. Solid foods require much more pressure to push backward through the mouth and throat than liquids do, and generating this additional pressure demands greater muscle strength. This can result in muscle weakness, which can then impede the ability to swallow. Chewing exercises or chopping food into small bites before eating can help significantly. Swallowing therapy often involves exercises to strengthen the muscles used in swallowing and to improve the muscle coordination during the swallowing process, along with learning safe swallowing strategies.
A SLP can teach the individual how to coordinate breathing and swallowing, while protecting the windpipe so no food or liquid enters the lungs. Specific exercises to strengthen tongue and lip function to promote faster swallowing may also be utilized.
Other treatment options include dietary changes such as adding a thickening agent to liquids, or avoiding certain types of food. Postural adjustments can also be beneficial. In severe cases, feeding tubes may be inserted directly into the stomach.
Some individuals are unaware of the need to swallow or are unable to feel it. They may suck on a lozenge to stimulate saliva production, which will stimulate more swallowing. (A sour candy stimulates more swallows than a milder or less flavorful lozenge.) In this way, these individuals can be trained to swallow more often and to receive cues from others.
Some people with MS experience dysphagia that gradually worsens over the course of the disease, whereas others experience temporary difficulty that gradually improves. Once improved, the swallowing problems may or may not return. "See your physician and SLP if your swallowing has changed," Lou advises. "These professionals can offer effective strategies to best manage the problem.
What can caregivers do?
Caregivers should be observant during mealtime to determine if swallowing and eating are slowing down or becoming more difficult. If so, the caregiver should remind the person about those strategies that have been recommended by the SLP. Sometimes in the course of a meal, a person may forget the proper head position, the proper amount of food or liquid taken per swallow, the time between a successful and unsuccessful swallow. Once the SLP has recommended specific strategies, the caregiver can provide gentle reminders/cues for the person to use these strategies successfully.
Also, the caregiver should be familiar with the Heimlich maneuver, an emergency procedure for removing a foreign object lodged in the airway and preventing the person from breathing. Remember that if the choking person is able to talk or cry, the Heimlich maneuver is not appropriate. For more information on the Heimlich Maneuver, call the American Heart Association at (800) 242-8721 or visit their website at www.amhrt.org.
Evaluation and Treatment of Swallowing Disorders By Jeri A. Logemann
(Last reviewed 7/2009)